Hiromitsu Ino, professor emeritus of nuclear engineering at the University of Tokyo: The removal of the fuel assemblies is “the right thing to do, because keeping the fuel up there is quite risky,” [he] says. Among the risks he and other experts cite is the possibility that a container being used to move the units falls and breaks apart, exposing the fuel to the air.
Hiroaki Koide, a nuclear scientist working at the University of Kyoto: [H]e was very worried about an accident, given the magnitude of the task. “I’m worried about whether Tepco can treat all the 1,331 [spent-fuel] assemblies without any problem and how long it will take,” he said.
Edwin Lyman, a nuclear expert with the Washington-based Union of Concerned Scientists: “The biggest risk with Unit 4 pool unloading is that a spent fuel cask might drop and damage the pool, causing a leak that could expose some fuel and cause overheating,” he said.
Hideyuki Ban, co-director of the Citizens’ Nuclear Information Center: [He] told Bellona in an email interview this week that he, too, was concerned about dropping casks and overheating in the pools.
Those employed by Tepco and another scientist disagree
Tepco’s Akira Ono, the head of the Fukushima plant: “We have removed spent fuels many times. Therefore, we don’t think we are going to be doing anything that is very dangerous.”
Tepco adviser Lake Barrett: “A fuel assembly in this state has the heat output of a few toasters. Worldwide experience with a few dropped or damaged fuel assemblies has not resulted in any off-site impact.”
Thomas Cochran, Natural Resource Defense Council’s nuclear program senior scientist: [He] told Bellona that a dropped fuel assembly was unlikely to cause wide spread contamination. But Cochran was skeptical that a dropped assembly would even break. “The vast majority of fission materials are encased in ceramic material – if a fuel assemble casing broke, you would be dealing with noble gasses as well as a small amount of radioactive ones, but I don’t think that would cause any sign of off site exposure,” he said.
See also: Warning from Japan's Top Nuclear Official: I am "much more worried" about fuel in Fukushima Unit 4 -- Rods may break open and release highly radioactive material -- Beware risks from debris, a disaster if damaged -- Removal may start Nov. 8
Published: November 8th, 2013 at 12:14 pm ET
- Warning from Japan’s Top Nuclear Official: I am “much more worried” about fuel in Fukushima Unit 4 — Rods may break open and release highly radioactive material — Beware risks from debris, a disaster if damaged — Removal may start Nov. 8 October 30, 2013
- Tepco Adviser: “Everyone in the world” will be safer if fuel rods transferred from Fukushima Unit 4 — WSJ: Global concern over removal process (VIDEO) November 18, 2013
- Tepco Adviser: 925 quadrillion Bq of contaminated water from trying to cool melted Fukushima cores in first few months after 3/11 — TV: “Tepco has no idea where the fuel is” (VIDEO) November 23, 2013
- NYTimes: Countries increasingly worried about Fukushima Unit 4 spent fuel — Experts: Concern over potential cracks in pool walls — Professors: “In deteriorating condition”; “This is a critical global issue”; “Could have fatal consequences for Japan” September 6, 2013
- AP: Experts warn about ground sinking at Fukushima plant — Tepco Adviser: Reactor building structures likely degraded; “Containment degradation” concerns back in 2011 December 3, 2013